A5084079543- Nuclear physics research studies
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Astronomical and nuclear sciences
- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- Advanced Chemical Physics Studies
- Advanced NMR Techniques and Applications
- Atomic and Subatomic Physics Research
- Nuclear reactor physics and engineering
- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Particle Detector Development and Performance
- Superconducting Materials and Applications
- Radiation Detection and Scintillator Technologies
- Quantum, superfluid, helium dynamics
- Rare-earth and actinide compounds
- Planetary Science and Exploration
- Microstructure and Mechanical Properties of Steels
- Neutrino Physics Research
- Radiation Therapy and Dosimetry
- Magnetic Properties and Applications
- Space Exploration and Technology
Ursinus College
2012-2024
Lund University
2016
GSI Helmholtz Centre for Heavy Ion Research
2016
Earlham College
2000-2007
Florida State University
1997-2000
Southwest Research Institute
1993-1994
Lowell Observatory
1969-1974
Both one-proton and one-neutron knockout reactions were performed with fast beams of two asymmetric, neutron-deficient rare isotopes produced by projectile fragmentation. The are used to probe the nucleon spectroscopic strengths at both weakly strongly bound Fermi surfaces. $^{9}\mathrm{Be}$($^{28}\mathrm{S}$,$^{27}\mathrm{P}$)X $^{9}\mathrm{Be}$($^{24}\mathrm{Si}$,$^{23}\mathrm{Al}$)X valence proton states $^{9}\mathrm{Be}$($^{28}\mathrm{S}$, $^{27}\mathrm{S}$)X...
A new technique to measure $(p,n)$ charge-exchange reactions in inverse kinematics at intermediate energies on unstable isotopes was successfully developed and used study the $^{56}\mathrm{Ni}(p,n)$ reaction $110\text{ }\text{ }\mathrm{MeV}/\mathrm{u}$. Gamow-Teller transition strengths from $^{56}\mathrm{Ni}$ leading $^{56}\mathrm{Cu}$ were obtained compared with shell-model predictions $pf$ shell using KB3G GXPF1A interactions. The calculations interaction reproduce experimental strength...
The 9Be(32Ar, 31Ar)X reaction, leading to the 5/2+ ground state of a nucleus at proton drip line, has cross section 10.4(13) mb beam energy 65.1 MeV/nucleon. This translates into spectroscopic factor that is only 24(3)% predicted by many-body shell-model theory. We introduce refinements eikonal reaction theory used extract clarify this very strong reduction represents an effect nuclear structure. suggest it reflects correlation effects linked high neutron separation (22.0 MeV) for state.
Although descriptions of the effect stress on spontaneous magnetization within a single domain already exist, there remains no adequate mathematical model for effects noncoaxial magnetic field and bulk in multidomained specimen. This article addresses problem provides phenomenological theory that applies to case isotropic materials. The magnetomechanical hysteresis Sablik Jiles is thus extended treat properties an isotropic, polycrystalline medium. In modeling, noncollinearity between taken...
The degree of collectivity in the neutron-rich nuclei $^{32}\mathrm{Mg}$ and $^{34}\mathrm{Mg}$ has been determined via intermediate-energy Coulomb excitation inverse kinematics. Measured energies first excited ${2}^{+}$ states reduced electric quadrupole transition probabilities $B(E2;{0}_{\text{g.s.}}^{+}\ensuremath{\rightarrow}{2}_{1}^{+})$ are presented for $^{34}\mathrm{Mg}$. results agree with previous measurements confirm placement both within ``island inversion.''
The first excited state in the neutron-rich N=20 isotope ${}^{31}\mathrm{Na}$ was observed at 350(20) keV via intermediate energy heavy-ion scattering, which is dominated by Coulomb excitation mechanism. This appears to be a rotational built on strongly deformed ground state. yield of \ensuremath{\gamma} ray deexciting this can reproduced shell model calculation takes $\ensuremath{\nu}{(f}_{7/2}{,p}_{3/2})$ intruder configurations into account.
The $^{9}\mathrm{Be}(^{46}\mathrm{Ar},^{45}\mathrm{Ar}+\ensuremath{\gamma})X$ one-neutron removal reaction has been studied in inverse kinematics at 70 MeV/nucleon. Coincidences with \ensuremath{\gamma} rays served to disentangle knockout events leading the $^{45}\mathrm{Ar}$ ground state. measured partial cross section corresponds a spectroscopic factor of 4.9(7). residue momentum distribution is compared new calculations based on eikonal theory and represents first case an...
Background: Gamow-Teller (GT) transition strength distributions in stable and unstable $pf$-shell isotopes are key inputs for estimating electron-capture rates important stellar evolution. Charge-exchange experiments at intermediate beam energies have long been used to test theoretical predictions GT strengths, but previous were largely restricted nuclei. Since a large fraction of the nuclei relevant astrophysical applications (including such as ${}^{56}$Ni) unstable, new methods needed...
One-neutron knockout reactions from the deeply bound $N=16$ isotones with $Z=16,17,$ and 18 have been studied in inverse kinematics intermediate-energy beams. $\ensuremath{\gamma}$-ray spectroscopy coincidence detection of residues allowed for an investigation one-neutron removal leading to individual excited states. Spectroscopic factors are deduced framework sudden eikonal approximations compared USD shell-model predictions. The momentum distributions observed experiment used identify...
The energy of the first excited state in neutron-rich $N=28$ nucleus $^{45}\mathrm{Cl}$ has been established via in-beam \ensuremath{\gamma}-ray spectroscopy following proton removal. This value completes systematics $E(1/{2}_{1}^{+})\ensuremath{-}E(3/{2}_{1}^{+})$ level spacing odd-mass K, Cl, and P isotopes for $N=20\text{\ensuremath{-}}28$. results are discussed framework shell-model calculations $\mathit{sd}\text{\ensuremath{-}}\mathit{fp}$ model space. contribution central, spin-orbit,...
Elastic and inelastic proton scattering has been measured in inverse kinematics on the unstable nucleus ${}^{40}\mathrm{S}$. A phenomenological distorted wave Born approximation analysis yields a quadrupole deformation parameter ${\ensuremath{\beta}}_{2}=0.35\ifmmode\pm\else\textpm\fi{}0.05$ for ${2}_{1}^{+}$ state. Consistent microscopic analyses have applied to all even-even sulfur isotopes from $A=32$ $A=40$. The second used collective model densities modified Jeukenne-Lejeune-Mahaux...
Intermediate-energy Coulomb excitation is a key method to investigate collectivity in exotic nuclei far from $\ensuremath{\beta}$ stability. We report on the measurement of absolute ${B(E2;0}_{1}^{+}\ensuremath{\rightarrow}{2}_{1}^{+})$ strength ${}^{46}\mathrm{Ar}$ for five different minimum impact parameters. Our findings underline validity, feasibility, and perspective this technique study also regime higher beam energy.
The isotopes $^{54}\mathrm{Ni}$, $^{56}\mathrm{Ni}$, and $^{58}\mathrm{Ni}$ have been studied via intermediate-energy Coulomb excitation at the National Superconducting Cyclotron Laboratory. Absolute $B(E2;{0}_{1}^{+}\ensuremath{\rightarrow}{2}_{1}^{+})$ strengths determined for all three nuclei using a consistent experimental approach, measure of quadrupole collectivity has established in vicinity much discussed doubly magic shell closure $N=Z=28$. energy strength to first ${2}^{+}$ state...
In the Ge-Sr mass region, isotopes with neutron number $N \leq 40$ are known to feature rapid shape changes both nucleon and angular momentum. To gain new insights into their structure, inelastic proton scattering experiments in inverse kinematics were performed on rare $^{74,76}$Kr. This work focuses observables related $J^{\pi} = 4^+_1$ states of Kr and, particular, hexadecapole degree freedom. By performing coupled-channels calculations, deformation parameters $\beta_4$ determined for...
We performed a measurement of the $^{51}\mathrm{V}(d,p)^{52}\mathrm{V}$ reaction at 16 MeV using Florida State University Super-Enge Split-Pole Spectrograph (SE-SPS) to search for single-neutron transfer strength ${g}_{9/2}$ intruder orbit. Measurements $\ensuremath{\nu}{g}_{9/2}$ with ($d,p$) reactions in $N=29$ isotones $^{49}\mathrm{Ca}, ^{51}\mathrm{Ti}, ^{53}\mathrm{Cr}$, and $^{55}\mathrm{Fe}$ have concluded that much expected is ``missing''; is, summed smaller than sum rule. In...
Low-lying excited states of $^{46}\mathrm{Ar}$ have been studied via inverse-kinematics proton scattering with a thick target. Coupled-channels calculations used to extract the deformation length ${2}_{1}^{+}$ state. This result, combined existing Coulomb excitation data, yields ratio neutron-to-proton transition matrix elements ${M}_{n}/{M}_{p}=1.19(25)N/Z$, showing departure from dominance observed in $N=28$ isotones above $^{48}\mathrm{Ca}$. The status shell below $^{48}\mathrm{Ca}$ is discussed.
We report on the use of one-proton knockout reaction from $^{44}\mathrm{S}$ to determine location ${d}_{5/2}$ proton strength in neutron-rich $^{43}\mathrm{P}$. The results are used test two shell-model frameworks with different pictures evolution single-proton energies along $N=28$ isotones near neutron dripline. observe a concentration hole 1 MeV excitation energy. This result favors recent interaction Utsuno et al. [Eur. Phys. J. Spec. Top. 150, 187 (2007)] and provides additional...
We have performed measurements of the ${0}_{\mathrm{g}.\mathrm{s}.}^{+}\ensuremath{\rightarrow}{2}_{1}^{+}$ excitations in neutron-rich isotopes $^{48,50}\mathrm{Ca}$ via inelastic proton scattering on a liquid hydrogen target, using GRETINA $\ensuremath{\gamma}$-ray tracking array. A comparison present results with those from previous lifetimes ${2}_{1}^{+}$ states provides ratio neutron and matrix elements for transitions. These allow determination effective charges to be used shell model...
The excitation cross sections to the first collective excitations in ${}^{28,30}\mathrm{Na}$ have been measured with technique of intermediate-energy heavy-ion scattering. trends deduced intrinsic electromagnetic quadrupole moments obtained present study and a previous ${}^{31}\mathrm{Na}$ suggest that ground state is dominated by intruder configurations, while lighter sodium isotopes are not. This conclusion supported data on binding energies.